The Gordon Research Conference on Neural Plasticity has been held in alternate years since 1977 in July at Brewster Academy, Wolfeboro, New Hampshire. We are requesting partial support for the Conference planned for July 19-23, 1993. The Gordon Research Conferences were established to stimulate scientific interchange in an informal setting. Uninhibited discussion is fostered by a rule prohibiting publication of the meetings and presentations, or indeed their citation. This format has proved particularly useful for the Conference on Neural Plasticity, a highly interdisciplinary meeting in which the subject of modifiability of the nervous system is examined at the molecular, cellular and systems levels. The participants in this meeting come from varied backgrounds (biochemical, pharmacological, anatomical, electrophysiological, behavioral, and computational) and find the opportunity for free exchange of ideas and information highly stimulating. For the 1993 Conference, one evening has been set aside for a keynote talk by Dr. Solomon Snyder, a leading scientist in the area of signal transduction in the brain. The remaining eight sessions will focus on specific issues of current interest. The formal speaking time is limited to allow for ample discussion. During the afternoon, no formal sessions are scheduled so that informal discussion can continue. As in past conferences, we will have poster sessions in the late afternoon as a further stimulus for mixing and discussion. Past participants have found that these informal interactions are one of the distinct advantages of the Gordon Conference format. The proposed program for 1993 includes sessions on: adaptive regulation of gene expression in the adult nervous system, molecular mechanisms of receptor regulation, regulation of synaptic transmission by nitric oxide, control of transmitter release at the molecular level, the molding of sensory systems by sensory inputs, conversion of short- term modulation into long-term structural changes, modulatory influences on simple neuronal networks, and the role of the amygdala in fear conditioning.